Chronic respiratory diseases are one of the major global health problems, and their treatment and management impose a huge burden on both patients’ quality of life and healthcare resources. Respiratory rehabilitation, as a non-pharmacological treatment, has received increasing attention in recent years. Oscillating positive expiratory pressure (OPEP) devices, as a new type of respiratory rehabilitation device, show good application prospects in improving respiratory function, promoting sputum expectoration, and improving quality of life. The purpose of this paper is to review the effect and mechanism of OPEP in respiratory rehabilitation.